5,000 hair-like antennae help manatees see and hear in murky water

SARASOTA, Fla. - Scientists at Mote Marine Laboratory have discovered secrets of manatees. The new research shows that sea cows have a more highly-tuned sense of touch than almost any other mammal – in sea or on land.

In murky waters of their real world, manatees see poorly, and find their way to food, less by sight and sound, and more by their sense of touch. “They have specialized hairs basically all over the body,” says Joseph Gaspard, Mote’s Manager of Animal Care, Training and Research.

Researchers at Mote knew that manatees have what they call "vibrissae" – 2,000 around their mouths, 3,000 on the rest of their bodies. What they have worked to learn for the past 15 years is how Hugh and Buffett, Mote's resident manatees, use them.

“If we can understand how they understand how they use their sense of touch, we can understand how they navigate through the water,” says Kat Nicolaisen, a Mote marine biologist.

Despite their intelligence, and no predators in the wild, manatees are endangered, thanks to man. The more scientists know about these mellow giants, they say, the better they can find ways to save them. In the meantime, these mammals with notoriously poor eyesight continue to open the eyes of those who study them.

“The thing that surprised me the most is how sensitive these guys are,” Nicolaisen says.

“They're able to detect the particles in those ripples moving at thousandths of a hair-width,” Gaspard says. Manatees can also tell from which direction a vibration comes, like human ears do with sound, except thousands of times over.

“You can think of it as they have 5,000 ears across their body,” Gaspard says. “How we localize sound is the timing differences, so if they're able to do that between two hairs, imagine if they can do that across 5,000, and that's what we think they can do.”

Mapping their world through vibrations in the water, and hairs on their bodies, these creatures without fingers touch their way through life.